Surrounding city centres and likely terrorist targets with “soft walls” will make it impossible for hijacked planes to get anywhere near them. So say the inventors of an avionics system that creates no-fly zones that pilots cannot breach.
Since the terrorist attacks on 11 September 2001, anti-aircraft missile batteries have been installed to protect buildings in Washington DC and other US cities.
Read more about an alternative way to stop planes entering certain zones.
Scary thing about it is what to do if a pilot needs to make a certain move to be able to make a safe emergency-landing… That move might become impossible with such a system.